This invention relates to a method and device for assembling a paper box by automatically folding an unfolded box paper along predetermined fold lines, and more specifically to a paper box assembling method and device applicable to making of a box body (lower box) and a lid box (upper box) for covering the box body, which can be transported and stored in its flat folded state and easily assembled fully in use with a simple operation.
The applicant has disclosed, in Japanese Unexamined Patent Publication No. HEI 9-219960(A1), a pullout-type paper box made of cardboard and comprising a square box bottom part having four sides, outer wall parts respectively connected to the sides of the box bottom part through double fold lines, inner wall parts respectively connected to the outer sides of the outer wall parts through double fold lines, and box-bottom abutting parts respectively connected to the outer sides of the inner wall parts through fold lines. That is, the disclosed paper-made box has double side walls formed of the outer wall parts and inner wall parts.
The aforenoted paper box made of cardboard having relative thick is formed in the flat state at a paper box factory and easily assembled in use. After assembled, the paper box can be returned to its flatly unfolded original state as occasion arises.
On the other hand, an ordinary paper box having fold-line parts opposite to each other in parallel on both sides has been assembled and subjected to usage in the customary way.
In most cases, the aforementioned pullout-type paper box has so far been assembled manually or marketed in its foldaway state. Thus, one worker can produce only 300 to 400 paper boxes of this type per day, and therefore, could not supply growing demand for paper boxes.
Furthermore, the conventional method for assembling the paper box was practiced manually, but the conventional assembling work consumes much time.
The present invention was made in the light of the aforenoted circumstances and has an object to provide a method and device for assembling a paper box capable of being produced on a large scale by automating the assembling of an ordinary paper box and pullout paper box and transported compact in its flatly folded state.
To attain the object described above according to the present invention there is provided a method for assembling a paper box having both side wall members unfolded and connected to a box bottom panel through a pair of parallel fold lines, which comprises a first process of carrying the aforesaid paper box having the aforesaid both side wall members unfolded at a folding station at which long guide members each being longer than the longitudinal length of the aforesaid paper box into spaces between the aforesaid fold lines and the aforesaid guide members with a minute clearance each formed on fixed stands and having both outer end portions between which a distance substantially equal to a distance between the aforesaid both side wall members is defined, so as to coincide the aforesaid fold lines with the both outer end portions of the aforesaid guide members in position, a second process of folding inward the aforesaid both side wall member on the basis of the outer end portions of the aforesaid guide members in contact with the aforesaid fold lines by operating interfolding means disposed on both sides of the aforesaid fixed stands, and a third process of pulling out the aforesaid paper box having the both side wall members folded from the aforementioned folding station while gripping the front side in relation to the forwarding direction of the aforesaid paper box.
The interfolding termed herein implies not only steadying of fold lines by folding, but also making of fold lines. The both side wall members mean portions on the outside of the parallel fold lines of the paper box.
The formation of the paper box as described above enables the fold lines to be steadily folded and a large number of paper boxes to be manufactured in a short period of time.
Besides, since the guide members are left secured in use, moving elements can be reduced in number, thus to decrease mechanical failure rate in operation.
On the upstream side of the folding station, there may be disposed an adhesive applying station to previously apply adhesive to prescribed inner portions of the both side wall members of the aforesaid paper box. By applying adhesive before interfolding the paper box, the folded parts can be maintained firmly and easily.
A paper box assembling device in a first embodiment according to the present invention for assembling a paper box having both side wall members unfolded and connected to a box bottom panel through parallel fold lines, comprises a folding station with fixed stands for placing the unfolded paper box thereon and a pair of guide members each being longer than the longitudinal length of the aforesaid paper box, which guide member is supported at the rear side in relation to the forwarding direction of the aforesaid paper box with a minute clearance formed on the fixed stands, which clearance has both outer end portions between which a distance substantially equal to a distance between the fold lines, and an interfolding mechanism including interfolding means disposed on both sides for folding inward the both side wall members of the aforesaid paper box placed on the aforesaid fixed stands, and a driving source for driving the interfolding means.
With the structure described above, the unfolded paper box can be steadily folded along the fold lines with securing the guide members.
The aforesaid interfolding mechanism may comprise a flexible sheet having basal portion fixed along the side end portions of the aforesaid fixed plates, an outer guide plate disposed on the intermediate part of the aforesaid flexible sheet and having the front end essentially abutting on the fold lines of the aforesaid paper box at the time of folding the paper box, the interfolding means secured on the front part of the aforesaid flexible sheet so as to cover the aforesaid side wall members at the time of folding, a lifting rod connected to the aforesaid interfolding means through a link member and disposed below the aforesaid fixed stands, and a drive means for driving the aforesaid lifting rod.
By lifting the lifting rod, the link member, interfolding means and outer guide plate are rotated to fold inward the paper box along the fold lines.
Since the flexible sheet is rotated simultaneously, the rotating axis is shifted in accordance with displacement of the fold lines of the paper box to be folded so as not to exert excessive force on the device.
On the front side of the aforesaid interfolding means, there may be provided an elastic plate for pressing the front side of the interfolding means at the time of folding the paper box.
According to the structure described above, the both side end portions of the paper box can be folded up into the inside of the fold line and firmly attached to each other. Moreover, in case of adhering, adhesion strength can be increased.
By adjusting the thickness of the guide member, the aforesaid fold line may be a double fold line. Even when adopting the double fold lines, the paper box can be neatly folded.
A paper box assembling device in a second embodiment according to the present invention for assembling a paper box having front, rear, left and right outer wall members connected to a square box bottom panel through pairs of first and second parallel fold lines, front, rear, left and right inner wall members connected to a square box bottom panel through pairs of third and fourth parallel fold lines, and side-panel connecting members connected to the respective side end portions of the adjoining outer wall members and provided on their intermediate portions with diagonal inward fold lines, which comprises a first folding station for allowing the aforesaid left and right inner wall members to be folded back inwardly along the aforesaid fourth fold line and adhered to the aforesaid left and right outer wall members through a first adhesive layer formed beforehand, a second folding station for allowing the aforesaid left and right outer wall members to be folded back inwardly along the aforesaid second fold line, folded up so as to overlap left and right peripheral edge portions of the aforesaid box bottom panel and allowing the aforesaid side-panel connecting members formed at the four corners thereof to be fold back inwardly along connecting fold lines extending from the aforesaid second fold line and adhered to the left and right peripheral edge portions of the aforesaid front and rear outer wall members corresponding to the aforesaid side-panel connecting members formed at the four corners through a second adhesive layer formed beforehand, a third folding station for allowing the aforesaid front and rear inner wall members to be folded inwardly along the aforesaid third fold line and adhered to the aforesaid front and rear outer wall members through the third adhesive layer formed beforehand, which first to third folding stations are each provided with fixed stands for allowing the aforesaid paper box to be placed thereon and a pair of interfolding mechanisms having interfolding means for folding the aforesaid outer or inner wall members inwardly, which interfolding means is disposed on both sides of the aforesaid fixed stands to fold inward the aforesaid outer wall members or inner wall members of the aforesaid paper box placed on the aforesaid fixed stands, while being in contact with the aforesaid outer wall members or inner wall members, and a driving source for driving the aforesaid interfolding means, which first and third folding stations each have a pair of guide members each being longer than the longitudinal length of the aforesaid paper box, which guide member is supported at the rear side in relation to the forwarding direction of the aforesaid paper box with a minute clearance formed on the fixed stands, which clearance has both outer end portions between which a distance substantially equal to a distance between the fold lines.
The front, rear, left and right are termed herein for the convenience of description for accounting for the paper box assembling device according to the present invention, but the front-to-rear and left-to-right relationships may of course be reversed.
With this mechanism, automation of assembling the paper box can be achieved by use of the multiple folding stations.
The paper box assembling device of the invention may further comprise a first adhesive applying station for forming the aforesaid first and second adhesive layers, which is placed on the upstream side of the aforesaid first folding station, and a second adhesive applying station for forming the aforesaid third adhesive layer, which is placed on the upstream side of the aforesaid third folding station, so that the aforesaid first adhesive layer is formed on a part of the inside of each of the aforesaid left and right outer wall members, the aforesaid second adhesive layers are formed on the forward-facing end portion of the front piece of the side-panel connecting members disposed at the four corners and the backward-facing end portion of the rear piece of the side-panel connecting members, and the third adhesive layer is formed on the outer sides of the front and rear inner wall members or the inner sides of the front and rear inner wall members. The distance between the inner end portions of the left and right outer wall member is substantially equal to the distance between inner side end portions of the left and right side-panel connecting members.
Thus, the first and second adhesive layers can be formed by allowing the paper box to pass a spray nozzle or coating roller for forming the adhesive layer. Since the first and second adhesive applying stations are on the respective upstream sides of the first and third folding stations, applying of the adhesive and folding of the portions applied with the adhesive can be carried out continuously so as to prevent the adhesive power of the adhesive applied to the paper box from being decreased on the way to the folding station.
The first adhesive applying station, first folding station and second folding station may be located on a first transfer conveyor, and the aforesaid second adhesive applying station and third folding station may be located on a second transfer conveyor arranged orthogonal to the first transfer conveyor for turning the aforesaid paper box 90 degrees. With this mechanism, the direction in which the paper box is fed can be changed, so that the direction in which the paper box is folded by the third folding station can be made parallel to that in which the paper box is folded by the first and second folding stations. The processes from applying the adhesive to the paper box to adhere the paper box can be continuously carried out with respect of each of the front-to-rear and left-to-right directions.